Adhesive applicator



NOV- 14, 1967 G; H. LocKwooD 3,352,279

ADHESIVE APPLICATOR Filed sept. l15, 1965 5 sheets-sheet 1 FIG-"l W7 zeINVENTOR 7 6L m//v oc/(M000 #fram/EK;

Nov. 14, 1967 G. H. LocKwooD 3,352,279

'ADHESIVE APPLIcAToR A Filed Sept. l5, v1965 Z Sheets-Sheet 2 /TCE` V-a3 m m29 4 52 FIG2 INVENTOR. 54m/N #flan/dana Nov. 14, 1967 G. HQLocKwooD 3,352,279

ADHES I VE APPLI CATOR Filed Sept. 15, 1965 E Sheets-Sheet Z FIG-4INVENTOR 6L mw M oc/(woop United States Patent O 3,352,279 ADHESIVEAPPLICATOR Glynn H. Lockwood, Carmel, Calif., assignor to LockwoodTechnical, Inc., a corporation of California Filed Sept. 15, 1965, Ser.No. 487,527 7 Claims. (Cl. 118-7) ABSTRACT OF THE DISCLSURE ble doctorblade on the reservoir engaging the applicator wheel.

My invention relates to devices for converting an adhesive in solid forminto an adhesive in liquid form and for applying the liquid adhesive toa receiving member; for example, a carton blank.

In the packaging of foods in cartons, as well as in many otherenvironments, it has become customary to apply adhesives in areas suchas strips or dot patterns or the like to panels of the containers inorder that the containers when erected will remain in the configurationdesired.

The preferable adhesive for use under these circumstances is one whichis solid under ordinary handling conditions and can be shipped, storedand utilized in its solid state. Iust prior to utilization on the cartonblank, the adhesive is changed from solid to liquid form by beingheated. One adhesive for this purpose is in the form of a circularcylinder several inches in diameter and a multiple of its diameter inlength. Since this body looks something like a candle, it is oftenreferred to as an adhesive candle.

It is an object of the invention to provide a machine for utilizing asolid body of adhesive and for converting that body into a liquidadhesive and then applying the liquid adhesive to an object to becoated.

Another object of the invention is to provide an adhesive applicator inwhich there is afforded a supply of liquid adhesive for an applicatorwheel, especially Ifor an applicator wheel having a pattern on it.

Another object of the invention is to provide an adhesive applicatorthat in a controlled way and automatically converts adhesive from solidform into a suitable supply of liquid adhesive for application.

Another object of the invention is to provide an adhesive applicator inwhich a predetermined level of liquid adhesive is maintained for use byan applicator wheel.

A still further object of the invention is to provide an adhesiveapplicator in which the machine readily sets or adjusts itself toaccommodate the adhesive applicator wheel.

Another object of the invention is to provide an automatic controlsystem for an adhesive applicator so that the supply of adhesive ismaintained at the desired rate. Another object of the invention is ingeneral to provide an improved adhesive applicator.

Other objects together with the foregoing are attained in the embodimentof the invention described in the accompanying description andillustrated in the accompanying drawings, in which:

FIGURE 1 is a side elevation of an adhesive applicator constructed inaccordance with the invention, various portions of the structure beingbroken away and disclosed in a cross section taken on a vertical plane;

FIGURE 2 is a plan of the structure shown in FIG- URE 1, portions beingbroken away to show the interior construction in cross section on ahorizontal plane and a portion of the device being removed for clarityof disclosure;

FIGURE 3 s a cross section, the plane of which is indicated by the line3-3 of FIGURE 2;

FIGURE 4 is an end elevation of the structure shown in the precedingfigures;

FIGURE 5 is a cross section on a vertical plane showing a modified formof level sensing device; and

FIGURE 6 is a cross section, the plane of which is indicated by the line6 6 of FIGURE 5.

While the adhesive applicator pursuant to the invention can beincorporated in a large number of different ways, depending in part uponthe particular installation in which it is to be utilized, it has inpractice been successfully embodied as disclosed herein.

in this environment the mechanism is designed for attachment to abracket 6 forming part of a mechanism over which carton blanks 7, forexample, are advanced in the direction of the arrow 8, the blanks beingat at this stage. They receive on a convenient (here the upper) surface9 thereof a sup-ply of liquid adhesive. Secured to the bracket 6 is afirst frame 11 from the top 12 of which projects a collar 13 receivingan upstanding tube 14 forming the support for a control and displaystand 16. This stand is a generally rectangular housing having variousindicators 17 and 18 thereon and having a manual control 19 foradjusting the temperature of the adhesive applicator. The control standis the terminal point for an electrical supply lead 21 from any suitablesource of electromotive force and serves also as the distributing pointfor various electrical connections and controls of the adhesiveapplicator.

The first `frame 11 serves as a journal mounting for a shaft 26preferably of tubular form and designed to rotate about an axis 27. Atone end, the shaft carries an overload or slipping clutch 28interconnecting the shaft with a drive sprocket 29 joined to anysuitable source of rotary power.

Fastened on the outboard end of the shaft 26 is an applicator wheel 31having a rim 32, the outside portion 33 of which is designed to holdliquid adhesive. The portion 33 of the applicator wheel is preferablyprovided with a number of adhesive receiving depressions 34 in anydesired pattern so that the adhesive deposit pattern is repeated oncefor each rotation of the applicator wheel as the applicator wheel comesinto physical contact with the upper surface 9 of the blank 7.

Since the temperature of the applicator wheel is an important factor,there is provided in a drum extension on the first frame 11 and withinthe rim 32 a number of electrical heaters 37 connected by appropriateleads 38 to the source of electrical energy 21 within the enclosure 16.Thus, as the applicator wheel is revolved about the axis 27 by the driveforce applied to the sprocket 29, the moving rim 32 is simultaneouslyheated and kept at the desired temperature.

The wheel rotates in juxtaposition with a bath of liquid adhesive. Forthat reason, there is provided an adhesive holding means. The holdingmeans includes a generally C-shaped second frame 41 adapted to be spacedsome distance from the periphery of the applicator wheel so as to leavean intervening reservoir 42 for liquid ad hesive. The frame 41 at eitherside carries separate plates 43 and 44 secured in position by fastenings46. The plates bear tightly against the sides ofthe applicator wheel topreclude any substantial leakage of liquid adhesive between the plates43 and 44 and the side faces of the applicator wheel.

The second frame 41 has a lower wall 47 extending close to but stoppingshort of the periphery of the applicator wheel. Disposed just below thewall 47 is a doctor blade 48. This is a relatively thin, springlymetallic member held in position by a bottom strap 49 fastened by screws51. The doctor blade is adjustable since it is perforated with elongatedapertures to lie around the fastenings 51 for the bottom strap 49 andits edge is abutted by an adjusting screw 52 set in the second frame 41.With this arrangement, the adjusting screw can be tightened or loosenedwhen the fastenings 51 are loose so as to move the doctor blade towardor permit it to retract from the surface of the applicator wheel. Oncethe desired adjustment has been attained, the screws 51 are tightenedand the doctor blade 48 is held in position so that there issubstantially no leakage between it and the applicator wheel.

The second frame 41 is movably mounted with respect to the first frame11. This is accomplished by providing a sleeve 56 having one endyextending rotatably through an opening 57 in the C-shaped frame 41 andhaving its other end firmly seated in an opening 58 in the first frame11. The sleeve is a circular cylindrical tube symmetrical about an axis59. The second frame 41 can rock or twist about the axis 59 with respectto the first frame 11. In order to preclude leakage despite thisrelative rocking motion, an O-ring 61 is interposed between the secondframe 41 and the sleeve 56. So that the relative rocking motion will notbe entirely unrestrained and to afford good backing for the doctor blade48, the first frame is provided with an adjusting screw 62 carrying aspring 63 urging a ball 64 against a face of the C-shaped frame 41. Byadjustment of the screw 62 the ball 64, in riding on the second frame41, imposes a force opposing the doctor blade thrust. The second frame41 is thus appropriately located. With this pivotal or floating mountingof the second frame, a close fit of the plates 43 and 44 and of thedoctor blade 48 is readily maintained despite slight variations intracking of the wheel 31 due to various causes.

In order to supply liquid adhesive to the applicator Wheel rim 32, thefirst frame 11 has a thermally insulated extension 66 formed of metalbut having a cover 6'7 of thermally insulating material held in place byfastenings 68. A tube 69 extends upwardly from the cover 67 and isenlarged to receive an insulating collar 71. Resting on the collar is atube 72 of the requisite diameter and height to receive at least onecandle 73 of solid adhesive material. The candle is a relatively loosefit within the tube 72 and at its bottom rests on a grid 74 spanning theinsulating collar 71. The grid is connected through the insulatingcollar 71 by a tiexible lead 75 to the electrical energy supply Withinthe housing 16. The grid 74 is thus electrically energized under propercontrol to become heated and to melt the solid adhesive at the bottom ofthe candle 73. This melted adhesive falls by gravity from the grid andtravels down through the tube 69 into a chamber 76 forming a receivingreservoir within the frame extension 66. When the grid 74 is operating,a pool 78 of liquid adhesive is provided within the chamber 76, beinglmaintained liquid and at proper temperature by an electric heater 79connected through a governing thermostat to the source of electricitywithin the enclosure 16.

So that a desired quantity of liquid adhesive will be maintained withinthe reservoir chamber 76, a temperature sensing probe 81 extends throughthe cover 67. The probe is fastened to a transverse support 82 acting asa heat sink and carried by a pair of heat radiating plates 83 secured tothe first frame 11 by fastenings 84. The probe 81 extends to connectionswithin the housing 16 and can be set by manipulation of a control 80 tobe effective at any desired valve. When the probe 81 is out of contactwith liquid adhesive, its temperature becornes relatively low. Thisfactor controls the grid energization so that the grid 74 is heated andsupplies additional liquid adhesive to the chamber 76. When the liquidadhesive level rises sufficiently to encompass the tip of the probe 8,1,the probe temperature is then brought up and the supply of energy to thegrid 74 is interrupted. By this means, the level 78 is maintained at adesired point.

The supply of liquid adhesive in the reservoir 76 tiows by gravitythrough a passageway 86 (FIG. 2) into a transverse bore 87 continuingthe passage 86 and opening onto an intersecting bore 88 in which thesleeve 56 is seated. In this way, the same level 78 maintained in thechamber 76 is also maintained in the reservoir 42 so that liquidadhesive at the desired level impinges against the adjacent surface ofthe applicator wheel. When the wheel 31 rotates, the depressions 34therein pick up liquid adhesive from the holder 42 and lcarry thematerial in the depressions past the doctor blade 48. The smoothperiphery of the wheel is wiped clean of adhesive. The charges ofadhesive are deposited from the depressions 34 onto the subjacent cardor carton blank 7 so as to form a pattern of applied adhesive thereonAAs the holder 42 becomes depleted, additional adhesive flows in from thechamber '76. As the level therein drops, the sensing device 81 energizesthe grid 74 to augment the supply by melting more of the candle, whichdescends by gravity as it is used.

As an alternative form of mechanism for controlling the level within thereservoir 76, there may be provided, as shown in FIGURES 5 and 6, anarrangement including a float 91 designed to be buoyant on the surface78 of the liquid adhesive. The particular level of the surface iscontrolled by an adjustment. The float 91 is supported on a trefoilspring leaf 92 having fastenings 93 at two of its ends securing the leafof a bridge 94 in turn fastened on the cover 67. Jam nuts 96 on thethreaded float stem provide for a level adjustment.

The extended central portion 97 of the spring leaf holds a magneticshield 98. The shield moves vertically with the float and approaches orrecedes from a reed switch 99 carried in a capsule 101 mounted within ahousing 102 on the cover 67. Bar magnets 103 on either side of the reedswitch establish a field that tends to hold the switch closed. When thelevel 78 rises and lifts the yfloat 91, the magnetic shield 98 moves toisolate the reed switch 99 from the field and permits the switch toassume its normally open position. This interrupts the supply ofelectricity to the grid 74. `On the other hand, when the level of theliquid 79 falls, the oat 91 descends and moves the magnetic shield 98 toexpose the reeds of the reed switch 99 to the field. This causes thereeds to close, thus energizing the circuit to the melting grid 74 an-dcauses a further liquefaction of the candle so that the level of theliquid adhesive in the reservoir 76 is raised.

The reservoir 7-6 is made of substantial volume, and its level thereforechanges slowly. To get an accelerated effect, the reservoir is dividedby a weir wall 106 so that melted adhesive'descending from the candle isinitially confined to the relatively small volume immediately around thefloat. This affords rapid response. -Extra liquid adhesive overflows theweir and is stored for use in the remainder of the reservoir and servesas a cushion to smooth out variations in tlow and to compensate for heatlag in some of the mechanism.

If desired, the probe 81 instead of extending into the chamber 76 can bedirected into the liquid in the reservoir 42. The agitation of theliquid by the wheel 31 tends to improve the temperature response of theprobe 81 and thus improves the uniformity of the level control.

What is claimed is:

1. An adhesive applicator comprising a first frame, an applicator wheelrotatably mounted on said rst frame,

a second frame for holding a bath of liquid adhesive around a portion ofthe periphery of said wheel, means on said first frame for receiving albody of solid adhesive, a heating grid spanning the bottom of saidreceiving means for supporting said body, means on said first frame forreceiving liquid adhesive from said grid, pivot means for supportingsaid second frame on said first frame for relative rotation about afixed axis, and means concentric with said axis for conducting liquidadhesive from said receiving means to said holding means.

2. An adhesive applicator comprising a first frame, an applicator Wheel,a sha-ft carrying said applicator Wheel and rotatably mounted in saidfirst frame, Wheel driving means on said shaft, a second frame, meanssupporting said second frame on said first frame for pivotal movementrelative thereto on a fixed axis normal to the axis of said Wheel, meanson said second frame for holding a bath for liquid adhesive in contactwith a .portion of the periphery of said Wheel, said holding meansincluding a doctor blade adapted to bear against the periphery of saidWheel, electrical means on said first frame and disposed around saidshaft for heating said Wheel, a tube upstanding from said first frameand adapted to receive a body of solid adhesive, an electrically heatedgrid spanning the bottom of said tube for supporting said body thereinand for melting adhesive from the bottom of said body, means on saidfirst frame for receiving melted adhesive from said grid, means on saidfirst frame and said second frame forming a passageway for said meltedadhesive between said receiving means and said holding means, and meanson said second frame and engaging said Wheel for holding said yWheel andsaid second frame in predetermined relation to each other.

3. A hot melt glue applicator comprising a first frame, a shaftjournalled in and projecting from said first frame, a heater cage ofannular form on said frame and disposed around the projecting portion ofsaid shaft, heater elements disposed in said heater cage, a patternwheel having a thermally conducting cylindrical rim, means lfor mountingsaid wheel on the projecting portion of said shaft with said rim spacedfrom and closely surrounding said heater cage, means defining a secondframe including a reservoir having bottom and side walls terminatingadjacent said pattern wheel rim, means for mounting said second frame onsaid first frame for rotation relative thereto about a fixed axissubstantially normal to the axis of said wheel, a planar doctor blade,and means for holding said planar doctor blade on said bottom Wall withthe end of said doctor blade against said pattern wheel rim.

4. A hot melt glue applicator as in claim 3 in which said reservoir andsaid heater elements are arranged in thermal communication through saidpattern wheel rim.

5. A hot melt glue applicator as in claim 3 in which said shaft has anaxis of rotation and said second frame mounting means provides rotationof said first frame about a second axis substantially normal to saidaxis of rotation.

6. A hot melt glue applicator as in claim 3 including side plates onsaid second frame engaging the side of said pattern Wheel rim ofaligning said second frame with said pattern wheel.

7. A hot melt glue applicator as in claim 3 in which said means formounting said second frame is a tube, and means for supplying saidreservoir with melted glue through said tube.

References Cited UNiTED STATES PATENTS 2,014,391 9/1935 MacKenzie118-261 2,399,688 5/1946- Metzner et al. 118-7 X 2,641,122 6/1953 Weberet al. 118-261 X 3,023,726 3/ 1962 Kamborian 118-7 X CHARLES A.WILLMUTH, Primary Examiner.

R. I. SMITH, Assistant Examiner.

1. AN ADHESIVE APPLICATOR COMPRISING A FIRST FRAME, AN APPLICTOR WHEELROTATABLY MOUNTED ON SAID FIRST FRAME, A SECOND FRAME FOR HOLDING A BATHOF LIQUID ADHESIVE AROUND A PORTION OF THE PERIPHERY OF SAID WHEEL,MEANS ON SAID FIRST FRAME FOR RECEIVING A BODY OF SOLID ADHESIVE, AHEATING GRID SPANNING THE BOTTOM OF SAID RECEIVING MEANS FOR SUPPORTINGSAID BODY, MEANS ON SAID FRIST FRAME FOR RECEIVING LIQUID ADHESIVE FROMSAID GRID, PIVOT MEANS FOR SUPPORTING SAID SECOND FRAME ON SAID FIRSTFRAME FOR RELATIVE ROTATION ABOUT A FIXED AXIS, AND MEANS CONCENTRICWITH SAID AXIS FOR CONDUCTING LIQUID ADHESIVE FROM SAID RECEIVING MEANSTO SAID HOLDING MEANS.